Flexible ac transmission system important questions

Flexible ac transmission system important questions

UNIT – I

2 MARKS

1.      What is the need of reactive power control in electrical power transmission lines?

2.      Distinguish between load compensation and system compensation

3.      What are the different types of compensation schemes?

4.      How the reactive power is controlled in FACTS devices?

5.      What is meant by Thyristor switched series capacitor?

6.      Draw the one line diagram of static synchronous series compensator.

7.      Write the formula for surge impedance of transmission system.

8.      Draw the circuit diagram and waveform of basic relationships for power flow control.

9.      Draw the one line diagram of UPFC.

10.  What is meant by IPFC?

11.  What are the advantages of the TCSC?

12.  What are modes of TCSC operation?

13.  Draw the V-I characteristics of the SVC

14.  Write three advantages and disadvantages of SVC.

16 MARKS

1.      Describe briefly the load and system compensation schemes.

2.      Explain the operation of UPFC with diagram.

3.      Explain the reactive power compensation at the sending, mid-point and receiving ends of the transmission lines.

4.      Explain the principle, working and characteristics of static VAR compensator with a neat circuit diagram.

5.      Explain the working and characteristics of Thyristor switched series capacitor with a neat diagram.

6.      Discuss briefly about the variation of the TCSC reactance with firing angle ‘alpha’.

7.      Explain the V-I capability characteristics of single module TCSC.

8.      Explain with neat circuit diagram about fixed capacitor-Thyristor controlled reactor.

UNIT – II

2 MARKS

1.      Draw the V-I characteristics of SVC

2.      State the advantages of slope in SVC dynamic characteristics.

3.      What are the different power electronic switching devices?

4.      Define voltage stability

5.      Define the term Static VAR Compensator

6.      State the advantages of linear operating characteristics of compensator

7.      Give any two characteristics of SVC

8.      Write any two applications of synchronous condensers

9.      What is UPFC

10.  What are the few approximations made in multi modal decomposition?

11.  What is thyristor switched capacitor?

12.  Define TCSC

13.  Draw the operating characteristics of SR compensator

16 MARKS

1.      Explain the design of SVC voltage regulator. Also discuss the influence of SVC on system voltage

2.      Discuss in detail the effect of SVC for the enhancement of transient stability.

3.      Using a general schematic diagram, explain the three basic modes of SVC control in detail.

4.      Explain the application of SVC for prevention of voltage instability.

5.      How do you enhance the damping in power system using SVC

6.      Explain the design of SVC voltage regulator and discuss the voltage control capability of SVC. What are the advantages of slope in dynamic characteristics of SVC?

7.      Discuss in detail about the role of SVC in improving the stability limit and enhancing the power system damping

8.      Describe the construction and operating characteristics of synchronous condensers.

9.      Derive and explain the series and shunt compensation of symmetrical transmission lines.

UNIT – III

2 MARKS

1.      What is the need of variable series compensation?

2.      Draw the schematic representation of TCSC.

3.      What are the different modes of operation of TCSC?

4.      How to model of TCSC?

5.      What are the applications of TCSC?

6.      Draw the V-I characteristics of TCSC

7.      Define line commutation

8.      Draw the controlled characteristics of Thyristor controlled reactor.

9.      What are the greatest advantages of VSC?

10.  Compare the conventional thyristor controlled-unified power flow controllers.

11.  What is FC-TCR?

12.  Draw the operating characteristics of SR compensator of FC-TCR without coupling transformer.

16 MARKS

1.      Explain the principle of operation of TCSC. Also discuss the different modes of TCSC.

2.      Explain the effect of TCSC for the enhancement of system damping.

3.      Explain the need for variable and fixed series compensation schemes.

4.      Describe the variable reactance model of TCSC.

5.      Explain the different modes of operation of TCSC.

6.      Describe the modeling of TCSC for load flow study.

7.      Explain the working, characteristics and operating modes of variable reactance model of thyristor controlled series capacitor.

8.      Explain in detail the applications of thyristor controlled series capacitor.

9.      How TCSC is used for the improvement of the stability of a system.

UNIT – IV

2 MARKS

1.      What is the function of STATCOM?

2.      Draw the phasor diagram illustrating the power flow control capabilities of UPFC.

3.      What is IPFC?

4.      Write the significance of sub synchronous resonance.

5.      State the salient features of UPFC

6.      Write any two assumptions made during the modeling of harmonic performance of SVC.

7.      Draw the block diagram of non linear gain in the SVC voltage regulator

16 MARKS

1.      With a neat sketch, explain the implementation of UPFC.

2.      Explain the working of STATCOM with a neat sketch. In what way it differs from SVC?

3.      Explain the operation of STATCOM with its V-I characteristics.

4.      Explain the performance of VSC based STATCOM.

5.      Describe the modeling of UPFC for power flow and transient stability studies.

6.      Explain the basic principle and control capability of unified power flow controller.

7.      Explain the power transfer capability of UPFC and compare its capabilities with other FACTS controllers.

8.      Describe the construction of UPFC with a block diagram and its characteristics with phasor diagrams.

9.      Explain the power flow control and oscillation damping in the two area system using UPFC.

UNIT – V

2 MARKS

1.      List the frequency ranges for different control interactions.

2.      What are the causes for SSR interactions?

3.      What do you understand by controller interactions?

4.      What is genetic algorithm?

5.      What is the need for co-ordination of different FACTS controllers?

6.      List the advantages of genetic algorithm.

7.      Write any three factors to test the effectiveness of SVC

8.      Write any two locations in which the SVCs are placed in the transmission system.

16 MARKS

1.      Using linear control techniques, explain the co-ordination of multiple controllers.

2.      Explain the controller interactions between multiple SVCs (SVC-SVC) in a large power system.

3.      Explain the FACTS controller interactions with similar, dissimilar HVDC controller links.

4.      Describe the genetic algorithm based control co-ordination of FACTS controllers.

5.      Explain the co-ordination of multiple controllers using genetic algorithm.